Technical Field
The present disclosure relates to a control device of a semiconductor switching element, and more particularly, to a control device of detecting an operation status of a switching element when an insulated gate bipolar transistor (IGBT) type switching element to which several thousand volts are applied is operated, such as a motor, an inverter, or a converter for various industrial applications, and operating at least one gate driver when driving the switching element based on the detected operation status.
Description of the Related Art
Generally, an IGBT type switching element for an industrial application may be classified based on characteristics such as a turn-on delay time, turn-off delay time, an amount of a current flowing at a collector terminal in a temperature range of 25 to 100 degrees Celsius (° C.), and the like. Also, a most popular VCE of the IGBT type switching element for an industrial application is in a voltage range of 600 to 1200 volts, and there is a tendency to use a VCE of 3300 volts.
That is, when an IGBT type switching element is used in industrial equipment such as a motor, an inverter, or a converter, a voltage between a collector terminal of the switching element and an emitter terminal thereof reaches several thousand volts. Also, an amount of a current flowing at the collector terminal may reach several hundred amperes (A).
FIG. 1 shows a control device of a typical semiconductor switching element.
Here, a user inputs a control instruction for operating a switching element to an interface (not shown), and the interface encodes input information. Thereafter, an encoded control signal is transmitted through an optical signal to a control unit 120 for controlling a switching element. At this point, encoded control information contained in the optical signal is converted into an electrical signal through an optical isolator 110. The optical signal containing the control information is converted into the electrical signal such that it may be possible to decrease unnecessary electrical noise or a short circuit possibility between two systems.
The converted electrical signal is transmitted to the control unit 120, and the control unit 120 may implement a logic circuit for decoding the encoded signal to generate a control signal based on the decoded signal. And, the control signal based on the decoded signal may be output to a gate driver 130. The gate driver 130 transmits a signal (current) to a gate terminal of a switching element 140 based on the received input signal to activate a switching operation of the switching element 140.
However, there is a problem in which a current (IC) for commencing turn-on and turn-off operations, which flows at a collector terminal of the switching element, is varied according to a voltage VCE having a wider voltage range of the collector terminal and an emitter terminal of such an IGBT type switching element. In addition, a switching operation of the IGBT type switching element is affected by properties of internal resistor and capacitor thereof, and the same IGBT type switching elements may have performances different from each other according to environment (temperature) at which they are provided.